Cutting tool having at least partially molded body and method of making same

ABSTRACT

A cutting tool for performing cutting operations on a workpiece when the cutting tool is rotated about a central axis by a machine tool, the cutting tool includes a generally cylindrical body disposed about the central axis. The generally cylindrical body includes a first end and an opposite second end. The cutting tool further includes a cutting portion and a mounting portion. The cutting portion is disposed at or about the first end of the generally cylindrical body and includes a number of cutting edges structured to engage the workpiece during cutting operations. The mounting portion is disposed at or about the opposite second end of the generally cylindrical body and is structured to be coupled to the machine tool. At least a portion of the generally cylindrical body comprises a molded portion formed via a molding process about the cutting portion in a manner that couples the cutting portion to the generally cylindrical body.

BACKGROUND

1. Field of the Invention

The invention relates generally to rotary cutting tools and, moreparticularly, to cutting tools having a generally cylindrical body, atleast a portion of which is formed via a molding process. The inventionfurther relates to a method for making such cutting tools.

2. Background Information

Rotary cutting tools, such as, for example, without limitation, drills,reamers, or endmills are commonly formed wholly from hardened toolsteels, from hardened tool steels coated with a secondary, hardenedmaterial, or formed from hardened tool steels provided with replaceablecutting inserts formed from other hardened materials such as, forexample, polycrystalline diamond (PCD), polycrystalline cubic boronnitride (PCBN), ceramic, cemented carbide, and cermet. While suchhardened materials generally produce a desirable final product, thecosts associated with producing such final product are generallyundesirable as the hardened materials typically require a large amountof time and machining in order to produce a finished product.

Although known rotary cutting tools have been generally suitable in manyapplications, there still exists room for improvement. For example, whena drill made from a single piece of carbide has been used to a pointwhere the cutting edges have become dull, the drill must either bedisposed of or reconditioned. In most cases, it is only the cuttingedges that are worn and not the rest of the cutting tool body. Disposalof the cutting tool obviously results in no further use of the tool.Reconditioning on the other hand, provides for further use of the tool,but such further use is often more limited than the original use and isaccompanied by a generally large reconditioning cost.

There is, therefore, a need for improved cutting tools.

SUMMARY OF THE INVENTION

Deficiencies in the prior art are addressed by embodiments of theinvention which are directed to an improved cutting tool and a method ofmaking the same.

As one aspect of the invention, a cutting tool for performing cuttingoperations on a workpiece when the cutting tool is rotated about acentral axis by a machine tool is provided. The cutting tool comprises:a generally cylindrical body disposed about the central axis, thegenerally cylindrical body having a first end and an opposite secondend; a cutting portion disposed at or about the first end of thegenerally cylindrical body, the cutting portion having a number ofcutting edges structured to engage the workpiece during cuttingoperations; and a mounting portion disposed at or about the oppositesecond end of the generally cylindrical body, the mounting portion beingstructured to be coupled to the machine tool. At least a portion of thegenerally cylindrical body comprises a molded portion formed via amolding process. The molded portion is formed about the cutting portionin a manner that couples the cutting portion to the generallycylindrical body.

The molded portion may be formed from fibers or particles disposedrandomly or in a predetermined ply structure disposed among/within amatrix material.

The cylindrical body portion may comprise a pre-formed inner coreportion disposed at or about the central axis and the molded portion maybe formed about the inner core portion. The inner core portion maycomprise one of a hollow tubular member or a solid cylindrical member.The inner core portion may be formed from one of steel, carbide,fiber-reinforced composite, or particle-reinforced composite.

The molded portion may comprise a number of wear resistant elementsdisposed or formed therein. The wear resistant elements may be formedfrom at least one of PCD, PCBN, carbide, cermet or ceramic.

The cylindrical body portion may include a number of chip evacuationflutes and the molded portion may comprise a number of wear resistantand/or thermal resistant particles disposed at or about the number offlutes.

The molded portion may comprise a number of wear resistant metal layersand/or shims disposed at or about the mounting portion.

The molded portion may comprise a number of cooling channels formedtherein.

The cutting portion may comprise a number of plate members coupled tothe cylindrical body via the molded portion and the number of cuttingedges may be formed in a number of cutting inserts selectively coupledto the number of plate members.

As another aspect of the invention, a method of forming a cutting toolfor use in rotary cutting operations is provided. The method comprises:providing a mold formed from one or more mold sections, the mold havinga number of internal surfaces which define an interior space within themold in the shape of the cutting tool; securing a cutting portion of thecutting tool within the mold; providing a quantity of settable materialwithin the interior space of the mold and about a portion of the cuttingportion to form a cutting tool within the mold; allowing the settablematerial to set; and removing the cutting tool from the mold.

The method may further comprise placing a core portion within the moldprior to providing the quantity of settable material within the mold andproviding the quantity of settable material within the mold may compriseproviding the settable material about the core portion.

The method may further comprise placing a number of tubular members inthe mold prior to providing the quantity of settable material within themold and providing the quantity of settable material within the mold maycomprise providing the material about the number of tubular members.

The quantity of settable material may be provided via an injectionprocess.

The quantity of settable material may be provided by drawing thesettable material into the interior space of the mold via a vacuumprocess.

The method may further comprise providing a number of wear resistantelements within the settable material.

The method may comprise electroplating a portion of the set materialafter removing the cutting tool from the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

A full understanding of the invention can be gained from the followingdescription of the preferred embodiments when read in conjunction withthe accompanying drawings in which:

FIG. 1 is an isometric view of a rotary cutting tool in accordance withan example embodiment of the present invention;

FIG. 2 is a cross-sectional view of the rotary cutting tool of FIG. 1taken along line 2-2;

FIG. 3 is a cross-sectional view of a rotary cutting tool in accordancewith another example embodiment of the present invention;

FIG. 4 is a cross-sectional view of a rotary cutting tool in accordancewith yet another example embodiment of the present invention;

FIG. 5 is an isometric view of a portion of a rotary cutting tool inaccordance with an example embodiment of the invention;

FIG. 6 is an isometric view of a portion of a rotary cutting tool inaccordance with a further example embodiment of the invention; and

FIG. 7 is a schematic isometric view of a mold for forming a cuttingtool in accordance with an example embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Directional phrases used herein, such as, for example, left, right,front, back, top, bottom and derivatives thereof, relate to theorientation of the elements shown in the drawings and are not limitingupon the claims unless expressly recited therein. Identical parts areprovided with the same reference number in all drawings.

As used herein, the term “number” shall be used to refer to any non-zeroquantity (i.e. one or any quantity greater than one).

FIG. 1 depicts an example cutting tool in accordance with a non-limitingembodiment of the present invention, for conducting rotary cuttingoperations on a workpiece (not shown) when cutting tool 10 is rotatedabout a central longitudinal axis 11. Cutting tool 10 includes agenerally cylindrical tool body 12 having a first end 14 and an oppositesecond end 16. Although cutting tool 10 is shown in the form of areamer, it is to be appreciated that the concepts described herein mayalso be applied to other rotary cutting tools such as, for example,without limitation, drills (e.g., single fluted, multi-fluted, helical,straight), modular drills, step drills, end mills, face mills, groovingtools, turning tools, boring bars, routers, taps, and circular saws.

Continuing to refer to FIG. 1, cutting tool 10 includes a cuttingportion 17 disposed generally at or about the first end 14 which isstructured to engage, and perform cutting operations on, a workpiece(not shown), when the cutting tool 10 is rotated about the centrallongitudinal axis 11. In the illustrated embodiment, cutting portion 17includes a plate member 18 disposed generally transverse to axis 11having a number (two in the illustrated embodiment) of cutting portions20 formed as a portion of, or coupled thereto (either permanently orselectively). As cutting tool 10 is depicted as a reamer in theembodiment illustrated in FIG. 1, the cutting portions 20 comprise tworeaming inserts, each selectively coupled to the plate member 18 suchthat each insert may be selectively removed and replaced as needed dueto wear and tear from use. Such selective coupling may be accomplishedthrough various means as commonly employed in the art for coupling aremovable insert to a cutting tool.

Continuing to refer to FIG. 1, cutting tool 10 further includes amounting portion 22 disposed generally at or about the second end 16that is adapted to be mounted in a chuck or other similar portion of amachine tool for rotating the cutting tool 10 about axis 11. One or moreflutes 23 which extend from the cutting portion 17 toward mountingportion 22 may be provided in tool body 12 to assist in evacuating chipsformed during cutting operations. Although shown having straight flutesin the example embodiment depicted, it is to be appreciated that theflutes provided in the tool body 12 may also be helical, of variousquantity, or other suitable arrangement without varying from the scopeof the present invention. It is to be appreciated that cutting tool 10may include any or all of the features previously described as well asother features of known cutting tools not particularly identified hereinwithout varying from the scope of the present invention.

Cutting tool 10 differs from known cutting tools in that all, or atleast a portion, of cylindrical body 12 is formed in a finished orsemi-finished state from a molding process. As shown in thecross-sectional view of FIG. 2, the entire tool body 12 of cutting tool10 is formed as a molded portion 24 formed via a molding process. Suchmolding process is carried out using a mold, such as mold 25 depictedschematically in FIG. 7. Mold 25 includes a number of internal surfaces26 which define an interior space 28 in the form of the outer shape ofthe cutting tool 10. Mold 25 is preferably formed from a suitable rigid,or semi-rigid material such as generally used for forming molds and maybe formed from, or include, a number of sections (not numbered) whichmay be coupled together to form the mold 25 and then subsequentlyuncoupled in order to facilitate removal of a formed cutting tool 10.Mold 24 includes one or more coupling mechanisms 30 for fixing cuttingportion 17 for cutting tool 10 in a precise location within the interiorspace 28. Although shown only schematically in FIG. 7, such couplingmechanism(s) may include clamps, screw-type precision locators, glue, orpins.

Preferably, molded portion 24 is thrilled from a composite material. Forexample, molded portion 24 may be formed from fibers or particlesdisposed randomly or in a predetermined ply structure disposedamong/within a settable matrix material. Such settable matrix materialmay be pre-impregnated with the fibers and later set during furtherprocessing or preferably is provided into the mold 25 via an injectionor vacuum process and then allowed to set. Examples of suitablematerials from which molded portion 24 may be formed include, withoutlimitation, reinforced plastics, carbon fiber composites, metal matrixcomposites, and metal alloys.

Additionally, all, or selected portions of, molded portion 24 may beformed from selected materials that are particularly resistant to hightemperatures or wear. For example, areas near the cutting portion 17 arecommonly subjected to high heat from cutting operations along withabrasive chips. Likewise, the chip evacuation portions of tool body 12(e.g., flutes 23), are also commonly subjected to such conditions.Portions 24′ of molded portion 24 of FIG. 1 show some non-limitingexamples of such areas that are desirably formed from temperature/wearresistant materials.

FIGS. 3 and 4 show cross-sectional views of example cutting tools 10′and 10″ in accordance with other embodiments of the present inventionwhich incorporate similar features as cutting tool 10 (e.g., withoutlimitation, flutes 23) but are formed in a slightly different manner.More particularly, cutting tools 10′ and 10″ show example embodiments inwhich a tool body 12′ and 12″ is formed from a molded portion 50 formedabout a preformed central core 52. In such examples, molded portion 50is generally formed as previously discussed. As shown in the exampleembodiment of FIG. 3, the core 52 may be formed from a solid,cylindrical member 60. As shown in the example embodiment of FIG. 4, thecore 52 may also be formed from a hollow tubular member 70. In eithercase, core 52 is preferably formed from steel, carbide, fiber-reinforcedcomposite, particle-reinforced composite, or other suitable material.The core 52 may be initially provided in an unstressed state oralternately may be pre-stressed prior to formation of molded portion 50thereabout. For example, the core 52 may be initially placed into amold, such as mold 25, in a radially stressed condition (i.e., twisted)prior to having molded portion 50 formed thereabout. Such pre-stressingof core 52 may be used to modify bending and torsional behavior.

Hollow tubular member 70 may be utilized as a coolant passage forproviding a flow of coolant through tool body 12″ generally to thecutting portion of the cutting tool 10″. Alternately, in certainapplications tubular member 70 may be used to provide a means forinternal chip evacuation from the cutting area adjacent the cuttingportion of the cutting tool 10″.

In order to increase durability and overall performance of the cuttingtool 10, one or more wear resistant elements disposed or formed therein.Such wear resistant elements may be formed, for example, withoutlimitation, from one or more PCD (polycrystalline diamond), PCBN(Polycrystalline Cubic Boron Nitride), carbide, cermet, ceramic or othersuitable material. For example, wear and/or thermal resistant particlesmay be incorporated into the molded portion adjacent the flutes in orderto help protect the flutes from detonating due to contact with hot andabrasive chips formed during cutting operations, such as previouslydiscussed in regard to portion 21′ of FIG. 1. Similarly, the portions ofmolded material at or about the flutes may be coated via anelectroplating process after the cutting tool has been formed in, andsubsequently removed from mold 25, in order to provide extra protectionto such areas.

As another example, such as shown in FIG. 5, the molded portion mayinclude a number of wear resistant metal layers and/or shims 70 disposedat or about the mounting portion 22 of cutting tool 10′″ to increase thestrength/wear resistance of the cutting tool at or about where it wouldbe mounted in a machine tool (not shown).

As yet another example, such as shown in FIG. 6, the molded portion mayinclude a number of wear resistant portions 72 molded therein at orabout the leading end (i.e., first end 14) of the cutting tool whichserve as guide pads for the cutting tool. Accordingly, portions 72 wouldtypically slightly extend outward from tool body 12.

In addition to wear resistant elements, other beneficial elements may bereadily incorporated into the molded portion of the cutting tool body.As an example, rigid or semi-rigid tubular members may be provided inmold 25 such that the molded portion would be formed generallythereabout. Once such molded portion is formed and the cutting tool isremoved from the mold, such tubular members may be employed as coolingchannels for use in helping to reduce temperatures in one or both of thetool body or cutting portion during cutting operations.

While specific embodiments of the invention have been described indetail herein, it will be appreciated by those skilled in the art thatvarious modifications and alternatives to those details could bedeveloped in light of the overall teachings of the disclosure.Accordingly, the particular arrangements disclosed are meant to beillustrative only and not limiting as to the scope of the inventionwhich is to be given the full breadth of the claims appended and any andall equivalents thereof.

What is claimed is:
 1. A cutting tool for performing cutting operationson a workpiece when the cutting tool is rotated about a central axis bya machine tool, the cutting tool comprising: a generally cylindricalbody disposed about the central axis, the generally cylindrical bodyhaving a first end and an opposite second end; a cutting portiondisposed at or about the first end of the generally cylindrical body,the cutting portion having a number of cutting edges structured toengage the workpiece during cutting operations; and a mounting portiondisposed at or about the opposite second end of the generallycylindrical body, the mounting portion being structured to be coupled tothe machine tool, wherein at least a portion of the generallycylindrical body comprises a molded portion formed via a moldingprocess, and wherein the molded portion is formed about the cuttingportion in a manner that couples the cutting portion to the generallycylindrical body.
 2. The cutting tool of claim 1 wherein the moldedportion comprises fibers or particles disposed randomly or in apredetermined ply structure disposed among/within a matrix material. 3.The cutting tool of claim 1 wherein the cylindrical body portioncomprises a pre-formed inner core portion disposed at or about thecentral axis and the molded portion is formed about the inner coreportion.
 4. The cutting tool of claim 3 wherein the inner core portioncomprises one of a hollow tubular member or a solid cylindrical member.5. The cutting tool of claim 3 wherein the inner core portion is formedfrom one of steel, carbide, fiber-reinforced composite, or particlereinforced composite.
 6. The cutting tool of claim 1 wherein the moldedportion comprises a number of wear resistant elements disposed or formedtherein.
 7. The cutting tool of claim 6 wherein the wear resistantelements are formed from at least one of PCD, PCBN, carbide, cermet orceramic.
 8. The cutting tool of claim 1 wherein the cylindrical bodyportion includes a number of chip evacuation flutes and wherein themolded portion comprises a number of wear resistant and/or thermalresistant particles disposed at or about the number of flutes.
 9. Thecuffing tool of claim 1 wherein the molded portion comprises a number ofwear and/or heat resistant metal layers and/or shims disposed at orabout at least one of the mounting portion and the cutting portion. 10.The cutting tool of claim 1 wherein the molded portion comprises anumber of cooling channels formed therein.
 11. The cuffing tool of claim1 wherein the cutting portion comprises a number of plate memberscoupled to the cylindrical body via the molded portion and wherein thenumber of cutting edges are formed in a number of cutting insertsselectively coupled to the number of plate members.
 12. A method offorming a cutting tool for use in rotary cutting operations, the methodcomprising: providing a mold formed from one or more mold sections, themold having a number of internal surfaces which define an interior spacewithin the mold in the shape of the cutting tool; securing a cuttingportion of the cutting tool within the mold; providing a quantity ofsettable material within the interior space of the mold and about aportion of the cutting portion to form a cutting tool within the mold;allowing the settable material to set; removing the cutting tool fromthe mold.
 13. The method of claim 12 further comprising placing a coreportion within the mold prior to providing the quantity of settablematerial within the mold, and wherein providing the quantity of settablematerial within the mold comprises providing the settable material aboutthe core portion.
 14. The method of claim 12 further comprising placinga number of tubular members in the mold prior to providing the quantityof settable material within the mold, and wherein providing the quantityof settable material within the mold comprises providing the materialabout the number of tubular members.
 15. The method of claim 12 whereinthe quantity of settable material is provided via an injection process.16. The method of claim 12 wherein the quantity of settable material isprovided by drawing the settable material into the interior space of themold via a vacuum process.
 17. The method of claim 12 further comprisingproviding a number of wear resistant elements within the settablematerial.
 18. The method of claim 12 further comprising electroplating aportion of the set material after removing the cutting tool from themold.